Ariadna thylacinus, Marsh & Stevens & Framenau, 2022

Marsh, Jessica R., Stevens, Mark I. & Framenau, Volker W., 2022, A taxonomic revision of the tube-web spiders of the genus Ariadna (Araneae: Segestriidae) in Tasmania, Zootaxa 5105 (2), pp. 151-201 : 189-194

publication ID	https://doi.org/ 10.11646/zootaxa.5105.2.1
publication LSID	lsid:zoobank.org:pub:4F6F5BC6-2AAF-4B23-882E-F77C63BE4CC2
DOI	https://doi.org/10.5281/zenodo.6333423
persistent identifier	https://treatment.plazi.org/id/35549E43-5F97-4724-A240-9AEF8954143C
taxon LSID	lsid:zoobank.org:act:35549E43-5F97-4724-A240-9AEF8954143C
treatment provided by	Plazi
scientific name	Ariadna thylacinus
status	sp. nov.

Treatment

Ariadna thylacinus View in CoL sp. nov.

Figs 34a–h View FIGURE 34 , 35a–c View FIGURE 35 , 36a–h View FIGURE 36 , 33 View FIGURE 33

http://zoobank.org/NomenclaturalActs/35549e43-5f97-4724-a240-9aef8954143c

Type material. Holotype ♂. AUSTRALIA: Tasmania: Flat Rock, 42.99°S; 147.95°E, coll. R. Raven, Bush Blitz expedition, 2010 ( TMAG J5352 View Materials ). GoogleMaps

Paratype ♀: same as holotype ( TMAG J5353 View Materials ) .

Other material examined. Tasmania: 1 ♂, same as holotype ( TMAG J4154 View Materials ) .

Etymology. The specific epithet is a noun in apposition and refers to the similarity of the transverse striations on the abdomen of this species to those of the Tasmanian tiger, Thylacinus cynocephalus ( Harris, 1808). It is hopefully not a predictor of the species’ future conservation status.

Diagnosis. Ariadna thylacinus sp. nov. is closest to A. alta sp. nov., A. amabilia sp. nov. and A. segmentata . It can be separated from A. segmentata by the male palp having a squared bulb, with a prominent rounded ventral projection which the embolus arises, and by the embolus arising from the dorso-central portion of the bulb ( Fig. 35a, b View FIGURE 35 cf. Figs 9a–c View FIGURE 9 , 27a–c View FIGURE 27 ). It is differentiated from A. alta sp. nov. by the lack of dual row of macrosetae proventrally on tibia I of females ( Fig. 36f, g View FIGURE 36 cf. Fig. 6f, g View FIGURE 6 ). It can be differentiated from A. amabilia sp. nov. by the oblong-square pedipalp bulb and the sinuous shape of the apical section of the embolus of A. thylacinus sp. nov., compared to the square bulb of A. amabilia sp. nov. and the smooth curve of the embolus apically ( Fig. 35a–c View FIGURE 35 cf. Fig. 9a–c View FIGURE 9 ). Ariadna tigrina sp. nov. is from the same type locality as A. thylacinus sp. nov., the two species can be differentiated by the shape of the pedipalp bulb, which is pyramidal in A. tigrina sp. nov., but rounded oblong in A. thylacinus sp. nov.; by the shape of the embolus, which is fine, smoothly curved and hooked apically in A. tigrina sp. nov., but is sinuous apically in A. thylacinus sp. nov. and by the pedipalp tibia, which is inflated in A. thylacinus sp. nov. ( Fig. 35a–c View FIGURE 35 cf. Fig. 38a–c View FIGURE 38 ).

Description. ♂ (based on holotype TMAG J5352). Total length 8.5.

Colour in ethanol: Carapace dark, reddish brown, becoming darker anteriorly, with raised caput area lighter red brown, bordered by darker red brown; sternum orange brown, maxillae orange brown, paler in colour apically, chelicerae reddish brown; abdomen dorsally pale cream, with nine dark grey, clearly defined chevrons, extended and joined medially, ventrally cream with dark patches centrally and laterally. Legs uniform golden brown. Figs 34a–h View FIGURE 34 .

Cephalothorax: 4.6 long, 3.1 wide, 2.5 high. Carapace oval, narrowing anteriorly, fovea a shallow indented pit, scattered sparse, dark setae, denser anteriorly ( Fig. 34a View FIGURE 34 ); caput raised towards anterior, highest just behind posterior eye row ( Fig. 34c View FIGURE 34 ). Labium narrowed anteriorly, about ¾ length of maxillae; chelicerae semi porrect with basal transverse ridge, retromargin with single tooth, promargin with three teeth; sternum elongated oval with precoxal triangles and with smaller, rounded intercoxal extensions, with sparse black setae ( Fig. 34b View FIGURE 34 ). Eye group 1.0 wide, 0.6 of anterior carapace width; posterior eye row straight, eye group occupying about a half of carapace width ( Fig. 34d View FIGURE 34 ).

Abdomen: 3.9 long; oval and tapering in shape, covered in sparse setae ( Fig. 34a View FIGURE 34 ).

Legs: Leg ratio: I>II>IV>III. Leg I femur 4.0, patella 1.3, tibia 3.7, metatarsus 3.7, tarsus 1.4. Leg II femur 4.0, patella 1.3, tibia 3.9, metatarsus 3.4, tarsus 1.3. Leg III femur 2.9, patella 1.3, tibia 2.1, metatarsus 2.0, tarsus 1.0. Leg IV femur 3.7, patella 1.2, tibia 2.8, metatarsus 1.5, tarsus 0.6. Covered in brown setae. Femur I bowed in dorsal view. Macrosetae: Leg I: Femur d2/1ap-dp2ap; tibia p1-2-1-2-1-2-2-1ap, v1-1-1-1-1-1-1ap, r1-1-1-1-1-1; metatarsus p1-1-1-1broken, r1-1-1-1-1ap. Leg II macrosetae femur d1-1/0-dp2ap; tibia p1-1-2-2, v1-1-1-1-1-1, r1-1-1- 1-1-2-1ap; metatarsus p2-1-2-1ap, v1-1ap, r1-1-1-1-1ap. Leg IV femur d1-1-1-dp1ap; tibia p1-1-1-1ap, r2-2-1ap; metatarsus p1, r2-1-2-1ap. Retrolateral distal preening comb with nine macrosetae ( Fig. 34e View FIGURE 34 ). STC I, II with seven teeth, ITC with small tooth. Tarsi with distal ventral scopulose setae.

Pedipalp: tibia short, about 1 ¼ the length of the cymbium and with a ventral median indention; cymbium rounded square shape, with anterior prolateral extension. Bulb squared-pyramidal in lateral view, embolus long, curved and sinuous apically ( Fig. 35a–c View FIGURE 35 ).

Description. ♀ (based on paratype, TMAG J5353). Total length 13.7.

Colour in ethanol: Carapace dark, reddish brown, darker around edges with sparse scattered setae, denser towards lateral edges and anteriorly. There is a pale area centrally demarking the raised caput, beginning anteriorly of fovea and bordered by darker red brown, with a darkened median line extending from fovea to half distance between fovea and eye group. Sternum red-brown, paler centrally, with moderately long, scattered dark setae. Labium darker brown, paler apically; maxillae orange brown, paler apically; chelicerae dark brown with dense, long, black setae. Abdomen with metallic sheen, dorsally grey, with faint paler, not well-defined chevrons; ventrally uniform grey. Legs red brown, covered with setae. Figs 36a–h View FIGURE 36 .

Cephalothorax: 5.5 long,3.2 wide, 2.0 high. Carapace rounded rectangular, with broad, square ‘neck’ anteriorly, anterior edge convex, posteriorly with defined median indent, fovea a shallow slit ( Fig. 36a View FIGURE 36 ); lateral profile domed, highest point at fovea ( Fig. 36c View FIGURE 36 ). Labium narrowed anteriorly, about ¾ length of maxillae; chelicerae broad, robust with basal transverse ridge, retromargin with single tooth, promargin with three teeth; sternum elongated oval with defined precoxal triangles and with rounded triangular intercoxal extensions ( Fig. 36b View FIGURE 36 ). Eye group 1.0 wide, 0.5 of anterior carapace width; posterior eye row slightly recurved, eyes small, three pairs of eyes widely separated, eye group occupying about 1/3 of carapace width ( Fig. 36d View FIGURE 36 ).

Abdomen: 8.2 long. Covered in fine dense setae ( Fig. 36a View FIGURE 36 ).

Legs: Leg ratio I>II>IV>III. Leg I femur 3.8, patella 1.4, tibia 2.8, metatarsus 2.4, tarsus 1.2. Leg II femur 3.9, patella 1.6, tibia 2.9, metatarsus 1.9, tarsus 0.9. Leg III femur 2.8, patella 1.1, tibia 2.1, metatarsus 1.7, tarsus 0.9. Leg IV femur 3.5, patella 1.1, tibia 2.3, metatarsus 2.2, tarsus 0.9. Femur I bowed in dorsal view. Macrosetae: Leg I femur dp2ap; tibia pv1, v2-2-2, pv1, rv1, v2, pv1, v2ap; metatarsus pv1-1-1, v2-2-2-2-2-1-2ap, rv1. Leg II femur dp1ap; tibia: p1-2, pv1ap, rv1-1-1-1-1ap; metatarsus: 2-2-1-2-1-2-1-2ap. Leg IV femur d1-1; tibia p1ap, v1-1/0; metatarsus rv1-1-1-1ap. Retrolateral distal preening comb with 9 macrosetae ( Fig. 36e View FIGURE 36 ), with two long macrosetae adjacent. STC I, II with 9 teeth, ITC with small tooth. Tarsi with distal ventral scopulose setae.

Pedipalp: With single, toothless claw, dense clusters of proventral macrosetae on tarsus and tibia; with dense scopulose setae on tarsus.

Genitalia: Despite the female appearing mature externally, with a sclerotised epigynal mound ( Fig. 36b View FIGURE 36 ), upon dissection the anterior receptaculum was very small and underdeveloped. This may be because the female was subadult, or had a physical deformity

Variation. Specimens examined were consistent in the colour and form of transverse abdominal markings and showed little variation in size.

Distribution. Known only from the type locality, Flat Rock, southeastern Tasmania ( Fig. 33 View FIGURE 33 ).